화학공학소재연구정보센터
Chemical Engineering Journal, Vol.360, 104-114, 2019
Attapulgite-supported nano-Fe-0/peroxymonsulfate for quinclorac removal: Performance, mechanism and degradation pathway
A nanocomposite of nZVI/ATP with nanoscale zero-valent iron(nZVI) supported on attapulgite(ATP) was synthesized for activating peroxymonosulfate (PMS) to generate reactive free radicals for quinclorac removal. The microstructures of nZVI/ATP were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, Scanning electron microscopy, and N-2 adsorption-desorption. The effect factors of nZVI/ATP-PMS system on quinclorac degradation were tested, including PMS dosage, nZVI/ATP dosage, initial solution pH, initial quinclorac concentration, common existing ions and temperature. Quinclorac degradation products were identified by LC-MS/MS, and the possible degradation mechanism was proposed. The results showed that nanoscale zerovalent iron (nZVI) was evenly dispersed on the attapulgite surface, which effectively prevents the agglomeration and oxidation of nZVI and improves its catalytic performance. The removal efficiency of quinclorac was 97.36%, in an hour using 0.5 g/L nZVI/ATP(3) and 10 mM PMS. The total organic carbon was removed as high as 79.97%. Quinclorac was degraded into five major products by chemical reactions of hydroxyl substitution, oxidation and ring-cleavage. Finally, most of the degradation products were mineralized into inorganics such as CO2, H2O or something else. It turned out that nZVI/ATP-PMS was a highly efficient catalytic degradation system for removing quinclorac residues in aqueous solution.